There has been a remarkable development of semiconductor light-emitting elements in recent years. In particular, a group III nitride compound semiconductor, such as gallium nitride (GaN), has become a focus of attention as a semiconductor material for short wavelength light. A group III nitride compound semiconductor is grown on a substrate made of various oxides or III-V compounds starting with sapphire single crystal.
Such a compound semiconductor is generally grown with a method such as the metal organic chemical vapor deposition (MOCVD) method, the molecular beam epitaxy (MBE) method or the hydride vapor phase epitaxy (HVPE) method.
In contrast, a sputtering (sputter) method in which particles (atoms or molecules) or the like having kinetic energy are made to collide against a substrate has been used for growth of a compound semiconductor.
Patent Document 1 describes a manufacturing method of a group III nitride compound semiconductor light-emitting element in which an intermediate layer made of at least a group III nitride compound is stacked on a substrate, and then an n-type semiconductor layer including a base layer, a light-emitting layer and a p-type semiconductor layer are sequentially stacked on the intermediate layer. The manufacturing method of a group III nitride compound semiconductor light-emitting element includes a preprocessing step for plasma processing on the substrate, and includes, following the preprocessing step, a sputtering step for forming a film of the intermediate layer on the substrate with a sputtering method.